Circuit breaker for ignition systems



March 5, 1968 D. D. WITHEM 3,372,249

CIRCUIT BREAKER FOR IGNITION SYSTEMS Filed May 12, 1966 I NVENTOR.Do/vnw D. W/THEM ATTORNEYS.

United States Patent 3,372,249 CIRCUIT BREAKER FOR IGNITION SYSTEMSDonald D. Withem, 7251 Pettibone Road, Chagrin Falls, Ohio 44022 FiledMay 12, 1966, Ser. No. 549,565 9 Claims. (Cl. 200-19) ABSTRACT OF THEDISCLOSURE A circuit breaker arrangement for an ignition system in whichthere are two cylindrical surfaces non-rotatably mounted on anengine-driven rotatable shaft of an internal combustion engine, thesurfaces being spatially disposed relative to each other along the axisof the shaft, a first of the surfaces being of electrical conductingmaterial around its circumference and a second of said surfaces being ofelectrical conducting material interrupted by electrical insulatingmaterial about its circumference, the electrical conducting material ofthe two cylindrical surfaces being in continuous electrical connectionthrough the shaft, a pair of rollers of electrically conductingmaterial, a first of the rollers being maintained in continuousengagement with the first of said surfaces during its rotation with theshaft, a second of said rollers being in continuous engagement with thesecond of said surfaces during its rotation with the shaft, one of saidrollers being electrically connected with one side of the ignitionsystem and the other of said rollers being electrically connected withthe other side of the ignition system, the second roller on engaging theinsulating material of the second surface breaking the circuit of theignition system, the said surfaces and rollers all being enclosed in aunitary housing which carries the rollers in position and which protectsthe rollers and surfaces from foreign material which might interferewith good electrical contact between rollers and the respectivesurfaces.

"are minimized or eliminated. In the prior circuit breakers utilized inthe distributors of ignition systems, wherein there are embodied makeand break contacts openand closed by a rubbing block which recurrentlymoves a contact bearing arm outwardly away and which resiliently .movesback after each movement imparted by the rubbing block, there areseveral deficiencies. One of these .deficiencies is the rapiddeterioration of the contacts through arcing between them and thephysical striking of the contacts together. Another of thesedeficiencies is the change in the spacing between contacts and theupsetting of the timing occurring through the progressive wearing awayof the rubbing block through frictional abrasion during the operation ofthe circuit breaker. My invention by avoiding the structure of suchprior circuit breakers obviates such difiiculties and shortcomings ofthe prior art. In my circuit breaker, there is a structure forintermittently breaking a circuit without intermittent radially outwardmovement of a contact arm provided by a rubbing block, and in whichresults of wear on parts 1 rubbing during rotation of one relative tothe other are inconsequential of minimal. Efficiency is readilymaintained, and repair and replacement of parts is greatly reduced,through the use of my new circuit breaker.

3,372,249 Patented Mar. 5, 1968 While deterioration of the contacts wasreduced internal combustion engines, the problems and difiicultiesarising from the wearing away of the rubbing blocks were not eliminatedin the prior circuit breakers used in such electronic ignition systems.Examples of such electronic ignition systems are shown in U.S. PatentsNo. 3,072,823 and No. 3,072,824.

An object of my invention is to provide a circuit breaker of unique andadvantageous structure for a distributor to be embodied in someavailable electronic ignition system, the circuit breaker having aneconomical and reliable construction whereby relatively maintenance-freeelectronic ignition systems may be more readily afforded by thepurchasing public.

Another object is the provision of a novel circuit breaker for adistributor to be embodied in some available electronic ignition system,in which circuit breaker mechanical wear is radically reduced and itseffect minimized or eliminated as compared with the mechanical wear onthe rubbing block and deterioration of contacts in the usual and priorcommon mechanical types of circuit breaker with their inherentdisadvantageous effects.

Another object is the provision of a unique circuit breaker fordistributors to be used in some available electronic ignition systemwhereby the dwell time of the said ignition system is not changednotwithstanding any mechanical wear that may occur in the circuitbreaker.

Another object is the provision of a new circuit breaker for adistributor to be embodied in an available ignition system which newcircuit breaker assures that the electrical timing of the ignitionsystem related to the rotation of the internal combustion engine is notsubstantially changed by, any mechanical wear of the circuit breaker.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawing, in which:

FIGURE 1 is a side elevational view, partially in section, of a combinedcircuit breaker and distributing mechanism in a housing, the whole unitbeing usually referred to as a distributor for an ignition system of aninternal combustion engine having multiple cylinders and sparkplugs, inthe example given here the engine having four cylinders and four sparkplugs;

FIGURE 2 is a plan view of the lower portion of the unit shown in FIGURE1, and looking in the direction of the arrows 2-2 of FIGURE 1;

FIGURE 3 is an enlarged view, partially in section, of a portion of theunit shown in FIGURE 2 and taken along the line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged view, partially in section, taken through theline 4-4 of FIGURE 1;

FIGURE 5 is an enlarged cross-sectional view taken through the line 5-5of FIGURE 2; and

FIGURE 6 is a diagrammatic view of the components and circuit of anelectronic ignition system for a four cylinder internal combustionengine, only one of the four spark plugs being depicted, and in which mynovel circuit breaker is embodied.

My distributor unit of my novel circuit breaker together with anappropriate distributing mechanism is indicated generally by thereference character 10. This unit 10 includes a metal housing 11, ofelectrical conducting properties, bolted to the engine structure, and acap or cover 31, of electrical insulating material such as moldedinsulating plastic material. The cap 31 fits over the open top of themetal housing 11 as shown in FIGURE 1 so as to be in axial alignmenttherewith and to enclose the chamber formed between housing 11 and cap31.

Extending through an opening in the bottom wall of housing 11, and inaxial alignment with the cylindrically shaped housing 11, is adistributor shaft 12 which is rotatable on its axis by the internalcombustion engine in the conventional manner so as to rotate insynchrony with the engine speed. The upper end of shaft 12 within theunit terminates in a flattened or noncircular end portion 15. This endportion 15 non-rotatably interfits with a head 34 of electricallyinsulating material forming a distributor arm which carries thereon torevolve therewith a revolving electrical contact element 33. The contactelement 33 is electrically interconnected through a usual spring armwith a centrally located electrical contact 35 in the well-known mannerso that the contact element 33 is at the same electrical potential ascentral contact element 35.

The distributor cap 31 of electrical insulating material carries thereona plurality (in the example given, four) electrical contact elements 32,each electrically connected to one pole or electrical terminal of ausual spark plug, of a set, such as four spark plugs, installed in theinternal combustion engine. These contact elements 32, electricallyinsulated from each other, are equidistantly spaced apart around areference circle and are electrically insulated from each other so thatthere is a flow of electrical current between central contact 35 and oneonly at a time of the plurality (four) of contacts 32.

Secured to one side of the metal housing 11 by a nut and bolt assemblyis a metal arcuate spring member 16H. The assembly 20 constitutes aterminal that is electrically connected with ground, that is, one sideof the circuit of the ignition system. The spring 16H being ofelectrically conducting material is thus electrically connected throughthe terminal 20 with ground.

Secured to the bottom wall of housing 11 spaced inwardly from thecylindrical wall of housing 11 is a pin 18, by means of the upsetportion 18A on the lower end of the pin. The axis of pin 18 is parallelto the axis of the housing 11. Carried on this pin 18 is an assemblydenoted generally by the reference character 16. This assembly 16includes a nylon supporting member 16E having a cylindrical portionfitting over and revolvable about pin 18, and an arm portion extendingoutwardly therefrom so as to pivotally swing about the axis of pin 18.

The outer or free end of metal spring 16H is secured by four metalrivets 16F to the nylon arm of electrically non-conducting member 16E. Asteel arm 16D is also secured to the nylon arm of member 16E by themetal rivets 16F. The end portion of spring 16H is on one side of thenylon arm and the steel arm 16D is on the other side of the nylon arm,and the spring 16H and arm 16D are electrically connected by the metalrivets 16F..

A metal pin 16B is carried on the free end of arm 16D so as to projectupwardly therefrom and having its axis parallel to the axis of pin 18and parallel to the axis of housing 11. Rotatably mounted on pin 16B bymeans of metal washers and bushing assembly 16C is a metal roller orwheel 16A. This wheel 16A is held in rolling engagement and electricalinterengagement with shaft 12. The bias and conformation of spring 16Hare such that the arm of nylon member 16B and steel arm 16D areresiliently urged to swing in a direction and with such force as to holdthe roller 16A against the steel shaft 12 as the shaft 12 rotates on itsaxis. Thus, the shaft 12 is maintained in good electrical connectionwith ground, that is, one side of the ignition circuit, through roller16A, assembly 16C, pin 16B, arm 16D, rivets 16F, spring 16H, andterminal or assembly 20 with its lead to ground.

As the shaft 12 within the chamber of the housing 11 is relatively cleanand free of grease and the like, an improved electrical connection ismaintained between the shaft 12 and ground. Were the electricalconnection attempted to be made between shaft 12 and ground at alocation outside of housing 11, such as where the shaft 12 is exposedbelow the housing 11, it would be difficult to effect and maintain agood electrical connection. Even a thin film of lubricant or otherforeign material on the shaft 12 interferes with a good electricalcontact made a roller held against the shaft at the location of suchAnother assembly denoted generally by the reference character 17 iscarried by the housing 11 diametrically opposite the assembly 16. Theconstruction of assembly 17 is the same as the construction of assembly16, except that pin 19 is shorter than pin 18 and the axial length ofthe cylindrical portion of member 17E rotatable on pin 19 is shorterthan the corresponding part of nylon member 16E. The terminal 21, madeup of nut and bolt assembly on the side wall of housing 11, similarlycarries metal spring 17H (similar to metal spring 16H) which biases themember 17E and steel arm 17D, interconnected with spring 17H throughmetal rivets 17F, to swing the rotatable roller 17A, carried by the freeend of arm 17D, radially inward toward the axis of shaft 12.

Non-rotatively mounted on shaft 12 so as to rotate therewith is a discor roller 13 disposed in the plane of roller 17A so as to be inengagement therewith. The disc or roller 13 is of metal except for aplurality of segments 14 of electrically non-conducting material such asnylon, hard rubber or other non-conducting plastic material. Thesesegments, in the illustration given of an ignition system for afour-cylinder internal combustion engine, are four in number. The fournon-conducting segments 14 are equidistantly spaced apart around thecylindrical periphery of the disc or roller 13. The remainder of disc orroller 13 is of electrically conducting material and is in electricalconnection with shaft 12 so that shaft 12 and disc 13 are substantiallyat the same electrical potential.

The terminal 21 is electrically insulated from the housing 11 and henceelectrically insulated from ground by the electrically insulating sleeve21A permitting the bolt of terminal 21 to pass through the wall ofhousing 11 without electrically contacting the same. The arm 17D ofassembly 17 is electrically connected to roller 17A which is resilientlybiased by spring 17H against the disc 13, that is, toward the axisthereof. As the shaft 12 and disc 13 rotate on their common axis, theroller 17A sequentially engages the outer metal wall of disc 13 and thesegments 14.

Upon the roller 17A being in engagement with the metal wall of disc 13,current may flow between terminals 20 and 21 through the assemblies 16and 17, shaft 12 and disc 13. However, upon the roller 17A being inengagement with one of the segments 14, then that flow of current isinterrupted or broken. Upon the shaft 12 and disc 13 rotating to wherethe roller 17A again is in engagement with the metal portion of the disc13, the said flow of current between terminals 20 and 21 isre-established.

Thus, the mechanism provides for a circuit breaker which sequentiallybreaks the current as the shaft 12 is rotated. The action remains thesame regardless of any wear on the parts. There is no snap action orquick swinging movement in or out of a contact arm. There is no rubbingblock to wear and thus cause maladjustment of the circuit breaker.

In FIGURE 6 there is illustrated diagrammatically and with parts beingshown in block form, my improved circuit breaker 10 embodied in anelectronic ignition system of an internal combustion engine, assumed forpurposes of example to have four cylinders and four spark plugs 39, onefor each cylinder.

The circuit breaker 10 is connected with ground through terminal 20. Theterminal 21 of the circuit breaker 10 is connected to terminal 25 of ausual and well-known electronic control unit 24. Another terminal 27 ofthe control unit 24 is connected through switch 22 with one pole orterminal of battery 23, the other pole or terminal of the battery beingconnected to ground. A third terminal 26 of the control unit 24 isconnected through winding 29 of ignition coil 28 to ground. The otherwinding 30 of ignition coil 28 is connected at one end to ground and atthe other end to electrical contact 35 carried by distributor cap 31.This contact 35 is electrically connected to revolvable contact member33 which sequentially engagesand electrically contacts equidistantlyspaced and electrically insulated contact elements 32. Each of the fourcontact elements in turn is connected with one pole or terminal of aspark plug 39, the other pole or terminal of which is electricallyconnected with ground. As the control unit 24 in itself is not part ofmy invention, it is shown in block form.

It is thus seen that my improved circuit breaker, of which an example isgiven as circuit breaker 10, provides to terminal 25 of the control unit24 in an electronic ignition system, a supply of electrical currentbroken or interrupted in accordance with the speed of rotation of shaft12, rotated in synchrony with the engine. The interruption or breakingof the electrical current is thus synchronized with the requirements ofthe spark plugs. The circuit breaker having the advantages heredescribed is peculiarly fitted for incorporation in such an ignitionsystem.

It is to be understood that segments 14 need not be of electricallyinsulating material but may be of electrical conducting material such asmetal but which is electrically insulated from the main metal bodyportion of disc member 13, whereby each segment is electricallyinsulated from shaft 12, and roller 17A when in engagement with asegment 14 is electrically insulated from shaft 12.

It is also to be understood that while it has been stated that theelectric current supplied for energizing the spark plugs isintermittently broken by my circuit breaker, this has been described ina brief manner as in fact the intermittently broken current is suppliedto electronic control unit 24 which in turn energizes a winding 29 ofcoil 28, which is the usual and well-known manner provides pulses ofelectrical energy to the spark plugs.

The present disclosure includes that contained in the appended claims,as well as that of the foregoing description.

Although this invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand the numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to Withoutdeparting from the spirit and scope of the invention as hereinafterclaimed.

What is claimed is:

1. In an electronic ignition system of an internal combustion enginehaving a plurality of spark plugs and having a distributor shaft ofelectrically conducting material rotated by the engine in synchrony withthe rotation thereof, said system including a housing concentricallymounted about said shaft, a circuit breaker comprising in combination afirst roller of electrically conducting material mounted within saidhousing and resiliently biased radially inward and against and inelectrical contact with the said shaft within said housing to maintaincontinuous electrical interconnection therebetween during full rotationof the shaft, first electrical connecting means connecting said firstroller with a first terminal carried by the housing adapted to beelectrically connected to one portion of the ignition system circuitwhereby said shaft is maintained continuously in electrical connectionwith said one portion of the said circuit, a disc member non-rotativelymounted on said shaft within said housing, said disc member having acylindrical outer surface concentric with said shaft, said disc memberhaving a body portion of electrically conducting material in electricalconnection with said shaft, said disc member including a plurality ofsegments electrically insulated from said body portion of electricallyconducting material substantially equidistantly spaced around saidcylindrical surface and alternating therearound with the electricallyconducting material of the body of said disc member, a second roller ofelectrically conducting material mounted within said housing andresiliently biased radially inward against the cylindrical surface ofsaid disc member, said second roller being in electrical contact withsaid shaft through the said body portion of the disc member upon theinterengagement of the second roller and the electrically conductingmaterial of the body of said disc member and being electricallyinsulated from said shaft upon the interengagement of the second rollerand one of said plurality of segments and not with said electricallyconducting material of said body, second electrical connection meansconnecting said second roller with a second terminal carried by thehousing adapted to be electrically connected to another portion of theignition system circuit whereby said shaft is intermittentlyelectrically connected with said another portion of said circuit uponthe second roller engaging the electrically conducting material of thebody of the disc member at said cylindrical surface and electricallydisconnected from said another portion of said circuit upon the secondroller engaging only one of said plurality of segments, the rotation ofsaid shaft and disc member therewith causing a making and a breaking ofthe current flow between said terminals in synchrony with the rotationof said shaft and disc member as the second roller sequentially engagessaid segments and the portion of body of the disc member separating saidsegments during rotation of the disc member.

2. A circuit breaker as claimed in claim 1 and in which said firstroller is carried by a first arcuate metal leaf spring that is carriedby the wall of the housing, said first leaf spring being directed andbiased to urge theroller toward the axis of said shaft, in which saidfirst electrical connecting means includes said first arcuate metal leafspring, in which said second roller is carried by a second arcuate metalleaf spring that is carried by the wall of the housing on a sideopposite of said shaft, said second leaf spring being directed andbiased to urge the roller toward the axis of said disc member, and inwhich said second electrical connecting means includes said secondarcuate metal leaf spring, the axes of said first and second rollers andof said shaft being parallel.

3. A circuit breaker as claimed in claim 1, and in which said firstroller is disposed in saidhousing in a first plane normal to the axis ofsaid shaft axially spaced from a second plane normal to the axis of saidshaft through both said disc member and the said second roller.

4. A circuit breaker as claimed in claim 1 and in which said housing isof electrical conducting material connected to ground, and one of saidterminals is electrically connected to said housing and the other ofsaid terminals is electrically insulated from said housing.

5. A circuit breaker as claimed in claim 1 and including a distributorcontact element connected to said shaft to be revolved thereby insynchrony with the rotation of said disc member, a plurality of spacedcontact elements insulated from each other and from said shaft and eachadapted to be connected to a separate spark plug of said engine, and inwhich said revolvable distributor contact element is supplied withelectrical potential for sequential supply to said spaced contactelements in accordance with electrical energy effected by the making andbreaking of electrical current in accordance with the rotation of saiddisc member relative to said second roller sequentially engaging saidsegments and said body of electrical- 1y conducting material.

6. A circuit breaker mechanism for incorporation in the circuit of anelectronic ignition system for an internal combustion engine, in whichsaid ignition system requires an intermittent breaking of a circuit insynchrony with the rotation of the engine, the engine having adistributor shaft rotatable in synchrony with the rotation of theengine, said circuit breaker mechanism comprising in combination a firstcylindrical surface portion and a second cylindrical surface portionboth carried by and concentrically disposed about said shaft androtatable therewith, said first and second surface portions beingspatial- 1y disposed relative to each other axially of said shaft, afirst roller vhaving its axis parallel to the axis of said shaft anddisposed adjacent said first cylindrical surface to maintain constantengagement with the same during rotation of the shaft, a second rollerhaving its axis parallel to the axis of said shaft and disposed adjacentsaid second cylindrical surface to maintain constant engagement with thesame during rotation of the shaft, a housing enclosing both said surfaceportions and said rollers, said first and second rollers being ofelectrically conducting material, first electrical connecting meanscontinuously connecting said first roller and a first portion of thesaid circuit to conduct electrical current between said first portion ofthe circuit and said first roller and the said first cylindrical surfaceof said shaft engaged thereby, second electrical connecting meansconnecting said second roller and another portion of said circuit toconduct electrical current between said another portion of the saidcircuit and the said second cylindrical surface of said shaft engagedthereby, said first cylindrical surface being of electrical conductingmaterial and in continuous electrical contact during rotation of thefirst cylindrical surface with the first roller engaged thereby, saidsecond cylindrical surface having a plurality of first contact portionsand a plurality of second contact portions alternately disposed aroundthe circumference thereof, said first contact portions beingsubstantially equidistantly spaced from each other around thecircumference of said second cylindrical'portion and said second contactportions being substantially equidistantly spaced from each other aroundthe circumference of said second cylindrical surface, said first contactportions being of electrical conducting material and being electricallyconnected with said first cylindrical surface and the first rollerengaged thereby, said second contact portions being electricallyinsulated from said first contact portions and from first cylindricalsurface, the said second roller sequentially engaging said first andsecond contact portions as said second cylindrical surface rotates withsaid shaft to alternately electrically engage with said first contactportions to electrically connect through each said first contact portionengaged with said first cylindrical portion and the first roller engagedthereby, said second roller upon alternate engagement with each saidsecond contact portion being electrically insulated from said firstcylindrical surface and the first roller engaged thereby, the rotationof said cyindrical surfaces with said shaft intermittently breaking thecircuit therethrough between said rollers.

7. A circuit breaker as claimed in claim 6 and including first resilientmeans carried by said housing resiliently urging the first roller inengagement with said first cylindrical surface portion and secondresilient means carried by said housing resiliently urging the secondroller in engagement with said second cylindrical surface portion, saidfirst resilient means being included in said first electrical connectingmeans and said second resilient means being included in said secondelectrical connecting means.

8. A circuit breaker as claimed in claim 6 and in which said firstcylindrical surface is the peripheral circumferential surface of saidshaft, and said second cylindrical surface is provided by a cylindricalbody provided on said shaft and rotatable therewith and having a greaterdiameter than the diameter of said first cylindrical surface, saidcylindrical surfaces being disposed relative to each other axially ofsaid shaft.

9. A circuit breaker as claimed in claim 6 and in which said first andsecond rollers are carried by said housing, in which said housing is ofelectrical conducting material, and in which one of said electricconnecting means includes therein said housing and in which the other ofsaid electrical connecting means is electrically insulated from saidhousing.

References Cited UNITED STATES PATENTS 8/1923 Evans 200 24 4/1958Robertson 20024

